(a) The present invention relates to a microscope, and more particularly relates to a multiple-purpose microscope which enables its user to conduct various types or modes of microscopic examinations by a simplified examination mode changeover operation.
(b) Description of the Prior Art:
Recently, in such scientific technical fields as cell technology, there has been an increase in the number of instances wherein the same specimen is subjected to observations in various different types of microscopic examinations. For example, in case of an experiment of cell fusion which is conducted on two ova of a mouse, the nucleus of one of the ova is dyed with FITC (Fluorescein Isotyiocyanate), and the nucleus of the other ovum is dyed with TRITC (Tetramethl Rhodamine Isothiocynate), and thereafter these two ova are fused, and a Blue excitation beam is irradiated onto the resulting combined nucleic region. By observing the respective fluroscent beams consisting of a yellowish green light caused by FITC and a yellow light of TRITC reflected therefrom, the presence of cell fusion is confirmed. However, in case it is intended to observe the configuration of the nucleic region, it is not possible to attain the intended purpose by merely relying on a reflecting fluorescence microscopy such as mentioned above. Thus, one will have to rely on phase contrast microscopy or differential interference microscopy to accomplish the intended purpose. As discussed above, it should be noted that, in case many-phase observations of a single specimen are to be conducted, various types of microscopic examinations will have to be relied upon, such as phase contrast microscopy, differential interference microscopy, reflecting fluorescence microscopy and bright field microscopy. In such a case, it is desired that the microscope per se be so constructed as will permit as easy and simple changeover between various different modes of microscopic examinations as possible.
As a conventional example of such a multiple-purpose microscope as outlined above, there is the one which is of the arrangement that an insertion region is formed at the revolver area and either a dichroic mirror unit for reflecting fluorescence microscopy or a differential interference unit is inserted into the insertion region to thereby perform a switching of the mode of microscopic examination from one type to another. It should be noted, however, that in case of this known changeover type microscope, the point of intersection of the optical axis of the light-projecting tube which is the source of the fluorescent light, with the optical axis of observation will move as the revolver moves vertically for focusing, making it impossible to hold an optimum condition of illumination. As a result, there arise the inconvenience that uneven illumination is developed.